Infants and other incontinent individuals wear absorbent articles such as diapers to receive and contain urine and other body exudates. Absorbent articles function both to contain the discharged materials and to isolate these materials from the body of the wearer and from the wearer's garments and bed clothing. However, absorbent articles have a tendency to sag or gap away from and to slide/slip down on the body of the wearer during wear. This sagging/gapping and sliding/slipping is caused by the relative motions of the wearer as the wearer breathes, moves and changes positions, by the downward forces generated when the absorbent article is loaded with body exudates, and by the deformation of the materials of the absorbent article itself when subjected to such wearer's motions. This sagging/gapping and sliding/slipping of the absorbent article can lead to premature leakage and poor fit of the absorbent article about the wearer in the waist regions and the leg regions of the absorbent article.
In order to more snugly fit absorbent articles about the wearer, certain commercially available absorbent articles have been provided with elastic features. An example of a disposable diaper with an elastomeric waist feature which has achieved wide acceptance and commercial success is disclosed in U.S. Pat. No. 4,515,595 issued to Kievit and Osterhage on May 7, 1985. Elastic waist features will typically comprise an elasticized waistband consisting of an elastomeric member contractibly affixed between the topsheet and the backsheet. The elasticized waistband is, thus, designed to expand and contract with the wearer's motions and to maintain the fit of the absorbent article about the waist of the wearer during use. Disposable absorbent articles having elastic leg features are also known to the art. For example, U.S. Pat. No. 3,860,003, entitled "Contractable Side Portions For Disposable Diaper", issued to Buell on Jan. 14, 1975, describes an absorbent article having an elasticized leg cuff which has achieved wide acceptance and commercial success.
However, it has been found that the extension and contraction characteristics of elastic features on absorbent articles are limited or inhibited by the extension/contraction characteristics of the nonelastic webs making up the elastic feature. This problem is particularly encountered when the elastomeric member of the elastic feature comprises a heat shrinkable elastomeric material. The contraction of the heat shrinkable elastomer can be severely limited by the ability (lack thereof) of the nonelastic web(s) making up the elastic feature to contract.
Thus, it would be advantageous to provide an elastic feature for an absorbent article, particularly an elastic waist feature, that provides better extension/contraction characteristics in order to provide improved fit, reduced leakage, and wearer comfort.
Therefore, it is an object of the present invention to provide an absorbent article having an elastic feature, particularly an elastic waist feature, wherein one or more of the nonelastic webs forming the elastic feature is mechanically prestrained to enhance the performance of the elastic feature.
It is a further object of the present invention to provide a method and apparatus for mechanically stretching or prestraining at least a portion of one of the nonelastic webs of the elastic feature in such a way as to provide such an improved elastic feature.
These and other objects of the present invention will be more readily apparent when considered in reference to the following description and when taken in conjunction with the accompanying drawings.